brew install rename
See: http://plasmasturm.org/code/rename/
rename 's/hello/world/' *.txt
Rename hello.txt to world.txt and so on in *.txt.
hello.txt
world.txt
*.txt
rename -s .png .jpg.png *.png
Replace .png with .jpg.png in *.png.
.png
.jpg.png
*.png
-n
-l
-i
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